. Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below

a. What will be the action of gas on

i. dry litmus paper

ii.. moist litmus paper

b. Write a balanced chemical equation for the reaction taking place

Best Answer

Solution: a) When sulphur powder is burnt in the air sulphur-di-oxide is formed.

(i) Sulphur-di-oxide does not have any effect on dry litmus paper.

(ii) Sulphur-di-oxide turn the moist litmus paper from blue to red as contact of SO2 with water turns to sulfurous acid.

(b) S(s) + O2(g) → SO2(g)

SO2(g) + H2O →H2SO3

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